Background Recombinant human parathyroid hormone (1-34) (rhPTH (1 -34)) given by injection is a new seventh class drug of biological products, which is prepared by adopting gene recombination technique. rhPTH (1 -34) is mainly used to treat osteoporosis, especially for postmenopausal women.This study compared the clinical efficacy and safety of rhPTH (1-34) with elcatonin for treating postmenopausal women with osteoporosis in 11 urban areas of China. Methods Two hundred and five women with osteoporosis were enrolled in a 6-month, multicenter, randomized, controlled study. They were randomized to receive either rhPTH (1-34) 20 ug (200 U) daily or elcatonin 20 U weekly. Lumbar spine (L1-4) and femoral neck bone mineral density (BMD), as well as biochemical markers of bone tover were measured. Adverse events were recorded.Results rhPTH (1-34) increased lumbar BMD significantly more than did elcatonin at 3 months and 6 months (2.38% vs 0.59%, P <0.05; 5.51% vs 1.55%, P <0.01), but there were no significant increases of BMD in these two groups at femoral neck. There were larger mean increases in bone markers in the rhPTH (1 -34) group than in the elcatonin group at 3 months and 6 months (serum bone-specific alkaline phosphatase (BSAP) 36.79% vs 0.31%; 92.42% vs -0.17%; urinary N-telopeptide/creatinine (NTX/Cr) 48.91% vs -5.32%; 68.82% vs -10.86%). Both treatments were well tolerated and there were no significant differences detected between the two groups in the proportion of any adverse events and any serious adverse events (67.0% vs 59.0%; 0 vs 0).Conclusions rhPTH (1-34) has more positive effects on bone formation, as shown by the larger increments of lumbar BMD and bone formation markers, than elcatonin, with only mild adverse events and no significant change in the liver, kidney or hematological indices.